Here's DT 770(pictures). Again, same driver, but this time, its' backside is covered with dampening cap(a plastic piece, filled with felt). This is DT 770 2005 edition-which is not a bass monster by any stretch. Maybe this cap is absent in Pro\80omh version and that's why it's a bass monster. I've tried to play them without this dampening cap and it sounded bad(too much bass). So if anyone can disassemble their pro\80 version-it's interesting to see if there's that cap or not.

So, the bottom line for Beyer owners: if you're not liking excessive bass-experiment with driver dampening from the back.

aah if this is so then the character of the 2 cans sonics are identical then (driverwise). If so, then I can now conclude that the dt880s are not for me. Hated the mids of the dt990s(for the price anyway). If they were $60, they would be a good value though.

enclosure, dampening, etc. affect sound much more than the driver. many have stated the midrange of the dt880s is a lot sweeter and better than dt990.

I just got some DT770/600's and I was shocked at how bass-shy they are - they have the least bass of any of the headphones I own. I am going to try them with different damping configurations and I will report back.

Edit: The sound sig is not just styled by the driver coverage or its absence, also the chassis interferes severely. I once tried to build myself a DT880 by implating 880 drivers into an old DT990 chassis - did ot work at all.

I remember having heard/read/whatever that the drivers are related - not the same. The question is: what does beyer consider "driver" and what "damping"? They're always talking about "systems" which seem to consist of driver (diaphragm and coil) and damping. So maybe I heard that the "systems" are related? Then the drivers itself may indeed be the same.

I just got some DT770/600's and I was shocked at how bass-shy they are - they have the least bass of any of the headphones I own. I am going to try them with different damping configurations and I will report back.

My 770/600's are VERY bass heavy - so we might want to look into any possible changes made in design over the years.
I have had mine for a long long time.
Bass heavy - lacking mids - very very bright.

I have added felt in front of the drivers and tried dampening the cups as well as adding felt to the back of the drivers.
They never came close to the sound of 880's.
I need to experiment some more.

Edit: The sound sig is not just styled by the driver coverage or its absence, also the chassis interferes severely. I once tried to build myself a DT880 by implating 880 drivers into an old DT990 chassis - did ot work at all.

That's correct of course. Older Beyer modifications were quite different. All 2005 editions share the same housing, except grills on the outer side.

when I removed the first black felt in front of the driver, my DT880 get a noticeable shaking bass, like my sold hd595 senns did at high volume
also now my cans are more direct, wider soundstage, clearer highs (less flat, more 'U'), and you feel new fatigue cause of that